1. Field of the Invention
This invention relates to a two-stage hydrodynamic pump and, more particularly, to a pump that uses hydrodynamic bearings that are lubricated by fluid that is pumped by the pump and that cools.
2. Description of the Related Art
Two-stage pumps have been utilized in the past. One such pump is shown and described in U.S. Pat. No. 7,048,520. Typically, such pumps utilize bearings for any rotating parts in the pump. Typically, the bearings were metal-to-metal bearings that required lubrication.
One downside of the two-stage pumps of the past is that the bearings and the metal-to-metal contact of any rotating bearing members reduced the useful life of the bearings and/or the pump.
What is needed, therefore, is a system and method for improving the pump and extending the useful life of the pump.